As the three friends, Chelsea, Riley, and Harper, arrive in Key West for Marilyn's surprise wedding, they quickly realize that their college girlfriend has changed in unexpected ways. Marilyn is now a successful entrepreneur with a glamorous lifestyle that is a far cry from her carefree college days.
Despite Marilyn's new persona, the bond between the four friends remains strong as they reminisce about their wild college adventures and support each other through various challenges. Chelsea, a struggling actress, is still hung up on her ex-boyfriend who broke her heart. Riley, a workaholic lawyer, is dealing with the pressures of her demanding career and difficult relationship with her fiancé. Harper, a free-spirited artist, is grappling with her fear of commitment and the consequences of her nomadic lifestyle.
As the wedding festivities ensue, old flames are rekindled, secrets are revealed, and new romances blossom. The group faces unexpected twists and turns that test their friendships and force them to confront their pasts. Through it all, they discover the true meaning of sisterhood and the importance of embracing change and following their hearts.
By the end of the weekend, each of the friends has gained new perspective on their lives and relationships, and they come to realize that true happiness lies in staying true to themselves and cherishing the bonds they share with the fabulous four.